A British backpacker missing in the scorching Australian outback for three days has told of how he did everything he could to survive - including drink his own urine and contact lens solution.

Sam Woodhead, 18, became lost after he set out for a jog from the remote Queensland cattle station where he had worked for less than two weeks.

But the chance discovery of packets of lenses in his rucksack - put there by his father, Peter - helped to keep him going for 72 hours in blistering temperatures of around 40C (104F).

Image Caption:Sam Woodhead was a keen long distance runner

The former Brighton College student, from Richmond upon Thames, London, also used his rugby shorts and other items of clothing to create an SOS sign that led to his rescue.

He was found about three miles away from the ranch by rescuers in a helicopter. He had lost two stones in weight and was just hours from death.

Video:Relieved Dad On Son's Survival

He told Sky News: "I feel very fortunate to be alive and to be standing here.

"I know that so many people helped out ... and I genuinely believe that if it wasn't for them, I wouldn't be here today.

"It was a really amazing feeling to be actually picked up and realise that I was actually going to make it through ... and it wasn't going to be the end."

His mother, Claire Derry, has visited him in hospital in Longreach, about 50 miles away from where he was discovered. She said he had lost weight and his kidneys were not working properly due to dehydration.

She said: "His birth was one of the best moments of my life, and this is pretty close to it, getting him back again, because I was pretty convinced it was touch and go. I did an awful lot of praying during that flight.

"He looks fantastic, he's suntanned, his mouth isn't blistered, he looks great, he's thinner and questionably a lot thinner than when I last saw him.

"The only concern is that his kidneys are not quite functioning normally and his blood's not normal. But that, the doctor says, is completely typical of somebody who's been completely dehydrated."

Ms Derry added: "He tried to drink his own urine. He said he'd run out of the contact lens fluid and the contact lens capsules said they were 69% water. But they'd all gone so the urine had become very, very concentrated.

"So he said he couldn't stomach it, so he had nothing, he had nothing to keep him going, by the time the helicopter crew got to him."

She told Sky News: "Sam is an amazingly cool guy and he said 'hi mum' and I said 'Sam I didn't think I would be holding you in my arms again frankly'.

"But he didn't cry and didn't show very much emotion at all. He just said I'm really happy to see you."

Mr Woodhead, who is set on joining the Armed Forces and is a keen long distance runner, is expected to leave hospital on Sunday.

Mike Curtin from Queensland State Police said: "He was quite disorientated but, you know, his body seemed to bounce back fairly quickly once he knew that obviously he was located and so forth and he was quite happy of the fact that someone had found him."

Mr Curtin warned of the harsh Australian climate and called on young people to be careful when travelling or working in the remote Australian Outback.

He said: "It's one of those things and I think there's a lesson to be learned here from any of these young fellows who do take, or young boys and girls, who take jobs in areas like this isolated part of the state, to be careful, to be safe, and prepare.

"And never take the harshest Australian environment and our climatic conditions here for granted."